This invention relates to forage harvester headers and more particularly to cutter means for severing crop as it enters the header for conveying and converging into the throat of a forage harvester to which the header is attached.
Forage harvesters for operation in row-planted crops such as corn are provided with multirow headers for cutting and conveying a row crop from a standing position in the field into a crop receiving throat of a harvester for processing. The header comprises a plurality of pairs of conveyors, each pair of conveyors corresponding to each individual row of crop to be cut and conveyed. In accordance with one well-known prior art design, an oscillating knife cutter is disposed adjacent to the crop entry position of each pair of conveyors at the front end of the header and is driven by a drive means interconnecting the oscillating knife cutter with a gear train at the rear end of the header. The drive means is comprised of a pitman-type reciprocatable rod connected at one end to the gear train at the rear end of the header and at the other end to a crank fixed to the oscillating knife of the cutter. A separate drive means for each oscillating knife cutter is provided. Examples of such cutter means are disclosed in U.S. Pat. Nos. 2,984,962 and 3,339,354. While this design has been found to perform satisfactorily from a functional point of view, it becomes unduly complex and costly for headers designed to accommodate a large number of rows such as, for example, a four-row header.
In accordance with one prior art experimental design of a four-row header, as generally disclosed in U.S. Pat. application, Ser. No. 074,265 (cross-referenced above) Sections II, IV, and VI, except for the cutter drive means used to interconnect an input drive gear train with each oscillating knife cutter. Each cutter drive means included a pitman-type reciprocatable rod connected at one end to an output shaft of an input drive gear train enclosed in a sealed gear case at the rear end of the header and at the other end to a crank fixed to a first of four oscillating knife cutters laterally spaced across the front end of the header. The cutter drive means for the second oscillating knife cutter was provided by a second reciprocatable rod connected at one end to the same output shaft of the input drive gear train and at the other end to a crank fixed to the second oscillating knife cutter. The cutter drive means for the third and fourth oscillating knife cutters was a mirror image of the cutter drive means for the first and second cutters. It was found that this design was unduly complicated and costly due to the requirement of providing for each cutter essentially identical cutter drive means extending from the rear of the header to the front of the header. As an example of the complexity and cost, the use of duplicative drive means resulted in the need for essentially duplicative adjustment, maintenance and repair procedures.